1. Field of the Invention
This invention relates to series and phase connectors for power station generators, and in particular to a method of making such connections and apparatus for performing such method.
2. Description of the Prior Art
The environment of the instant invention is that of large electrical generators, e.g., generators driven by turbines in a nuclear or other commercial power generating plant. The size and geometry of such generators requires that in constructing or repairing the stator coils, the coils must be placed in sections, or halves, and after they are in place those sections must be connected at their ends. Similarly, connections are required between the end of each phase coil and the parallel phase ring which circles around the end of the generator stator.
The standard prior procedure of assignee in the generator construction and repair art is that of individually fitting a connector by constructing a bundle of separate conductors. The problem presented is that the tolerance of construction of the coil sections is such that the positions of the coil ends to be connected vary within a tolerance of +/- one half inch, so that there is a range of about one inch in the variation of the coil ends which are to be joined. Further, the coil section ends, or headers, project axially from the end of the stator at an angle which may vary within some practical range. In the standard prior technique it has been necessary to wait until all the coil sections were in place in the stator, and then roll the stator to make the individual connections. Each connection has required the individual placing and bending into shape of a large number, e.g. 65, conductor sections which are squeezed together to make the connector portion. In this technique each conductor has to be hand bent to line it up properly, and then the connector must be soldered and brazed to the respective pair of header caps.
The above-described procedure has been necessarily a series operation, in the sense that little other work on the stator construction can progress while this operation is taking place. Up until this time, a job on a large generator in the field has taken typically one-two weeks for making the coil connections, involving a significant amount of time and cost. The problem is exacerbated in the repair of generators in nuclear power plants where a generator may be out of operation for only a limited amount of time while the fuel is being replenished. If the coil end connecting takes 1-2 weeks, the overall repair may not be completed by time the nuclear reactor is ready for operation, thus causing very expensive down-time of the entire plant. Thus, the need that has been presented is one of not only reducing the cost of the actual connection operation, but reducing the "cycle" time of recoiling the stator conductors, as well as time spent in building new units.
The approach of this invention has been to provide a novel technique for determining the geometry of the connector required for each series and/or phase connection as soon as the coil sections are in place. Thus, while coil construction and replacement is ongoing, information concerning the geometry of each required connection is used to separately machine the connectors for each required connection, which connectors can then be quickly clamped into position. Thus, the work of preparing the connectors can be carried on in parallel while the coil sections themselves are being placed, significantly reducing the overall time required for the operation.